FR3065810A1 - METHOD FOR DETECTING A DIFFERENCE IN A PHASE VOLTAGE OF AN ELECTRICAL NETWORK - Google Patents

Abstract

A method of detecting a phase voltage sag (Vp) comprising the steps of: - measuring, upstream of a breaking device and at regular intervals, the phase voltage (Vp) and a phase current ( Ip) flowing on a phase conductor (13); when the phase voltage falls below a predetermined voltage threshold, opening the breaking device; - following the opening of the breaking device, if the phase voltage resumes a normal voltage value defined as a function of the phase current (Ip), to detect a malfunction of the electric meter, to generate an alarm message , and keep open the cutoff organ; - following the opening of the cutoff member, if the phase voltage remains below the predetermined voltage threshold, detecting a collapse of the phase voltage (Vp), generating an alert message, and close the cutoff member (12).

Description

The invention relates to the management of electrical networks and more particularly the field of · methods of detecting a sag of a phase voltage of an electrical network.

BACKGROUND OF THE INVENTION

There are many reasons for a voltage drop in an electrical network that distributes electrical energy to electrical installations.

Among these reasons, one can cite an excessive consumption of electrical installations. Qn can also cite the shutdown of an electrical production unit, such as a hydroelectric power station or a nuclear power plant, due to maintenance operations, any breakdown, or conditions; inclement weather.

The voltage of the electrical network does not necessarily occur homogeneously on the electrical network. Generally, the electrical installations which are the most distant from the functional production units are the most affected.

The lowering of the voltage can have relatively significant consequences, both in terms of an electrical installation (degradation of the

25; operation of the electrical installation, failure ·) only at level; of the electrical network itself (voltage collapse due to cascaded shutdowns of several electrical production units ·}.

A drop in the voltage of the electrical network can; be · detected at an electric meter which measures the electric energy supplied to an electric installation by the electric network.

However, it should be ensured that:

The voltage failure detected by the: counter

35: electric; does not come from the electricity meter itself3065810 itself. The electric meter can in fact cause a local voltage drop. Among the related causes: · to the meter · and which can cause a drop in local voltage, we find · · “coaling” of a cut-off member of the meter. Some meters include a Cut-off device which allows you to selectively: connect and disconnect, remotely, the electrical installation and the electrical network. The contacts of the breaking device are: liable to be subjected to electric arcs which produce carbon deposits: on the contacts of the switching device. Coal mining refers to this phenomenon. Coal mining tends to • increase the resistance of: the breaking device when · it is closed. The order of magnitude of the typical increase in resistance of the breaking device is mQ. However, the current flowing: in the cut-off member can be very large, and can typically reach the value of 14 OA. Thus, the increase in resistance: of the cut-off member can cause the voltage at the electric meter to drop relatively significantly.

OBJECT OF THE INVENTION

The object of the invention is to detect, at the level of an electric meter, a sagging of a phase voltage of an electrical network, while ensuring that the sagging does not come from the electric meter itself. ·.

SUMMARY OF b * INVENTION

With a view to achieving this goal, a method for detecting a sag of a phase voltage is proposed, presented on a phase of an electrical network, the detection method being implemented by a counter. • electrical which is connected to the electrical network and which comprises a cut-off member mounted on a phase conductor connected to the phase, the: detection method comprising the steps:

- to measure, upstream of the breaking device and at regular intervals, the phase voltage and a phase current flowing on the phase conductor;

- when the phase voltage falls below a predetermined voltage threshold, to open the cut-off device;

- following the opening of the cut-off device, if the phase voltage returns to a normal voltage value defined as a function of the phase current, to detect a malfunction of the electric meter, to generate an alarm message to prevent malfunction of the electric meter, and keep the cut-off device open;

- following the opening of the cut-off device, if the phase voltage remains below the predetermined voltage threshold, to detect a sag of the phase voltage, to generate an alert message to prevent sagging of phase voltage, and to close the cut-off device.

The detection method therefore makes it possible both to detect a sag of the phase voltage, but also to ensure that the sag of the detected phase voltage comes from the electrical network and not from a malfunction of the electric meter itself. ,

An electric meter is further proposed comprising a cut-off member, a voltage sensor, a current sensor, a memory and a processing component arranged to implement the detection method which has just been described.

A computer program is also proposed comprising instructions for implementing, by an electric meter, the detection method which has just been described.

Storage means are further proposed, characterized: in that they; store a computer program comprising instructions for implementing, by an electric meter, the detection method which has just been described.

Other characteristics and advantages of the invention will emerge on reading the following description of particular non-limiting embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS:

Reference will be made to the appended drawings, among which:

- Figure 1 shows a single-phase electric meter in which is implemented the detection method according to a first embodiment of one invention;

- Figure 2 is a graph on which are represented reference points, a curve of upper bounds of reference intervals, a curve of lower bounds of reference intervals, and a new point;

- Figure 3 shows a three-phase electric meter in which is implemented · the detection method according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1, the method · for detecting a sag of a phase voltage of an electrical network according to a first embodiment of the invention is here. put; implemented by a single-phase electric meter 1.

The electrical network 2 is a single-phase electrical network, which includes a phase 3 and a neutral 4.

The count 1 is intended to measure an electrical energy consumption supplied by the electrical network 2 to an electrical installation 5,

The counter 1 comprises an upstream phase terminal 6a, a downstream phase terminal 6b, an upstream neutral terminal 7a and a downstream neutral terminal 7b.

The upstream phase terminal 6a is connected to the phase of the electrical network 2. The downstream phase terminal 6b is connected to a phase 8 of the electrical installation 5. The upstream neutral terminal 7a is connected to neutral 4 of the electrical network 2 The downstream neutral terminal 7b is connected to a neutral 9 of the electrical installation · h.

A disconnector 11 is positioned on the side of the electrical network 2, in order to be able to isolate from the electrical network 2 the electrical installation 5 when necessary.

The counter 1 further comprises a cut-off member mounted on a phase conductor 13 of the counter 1. The phase conductor 13 is connected to phase 3 of the electrical network 2 when the counter 1 is connected to the electrical network Z. L ' breaking device 12 is mounted between the upstream phase terminal 6a and the downstream phase terminal 6b.

The breaking device 12 makes it possible to selectively connect and disconnect, remotely, the electrical installation 5 from the electrical network 2 /.

The counter 1 further comprises a phase voltage sensor 15 and a phase current capior 16 /.

The phase voltage sensor 15 is symbolized by two resistors, but it is in reality possibly more complex.

The phase current sensor 16 is here a shunt.

The phase voltage sensor 15 and the phase current sensor 16 are located upstream of the cut-off member 12, that is to say on the side of the electrical network 2 relative to the cut-off member 12 .

The phase voltage sensor 15 measures a voltage of ^ phase lp which is equal to a difference between the potential of phase 3 and the potential of neutral 4 of the electrical network 2, The phase voltage Vp is. Here an alternating voltage of frequency equal to 50Hz and effective voltage equal to 230V.

The phase current sensor 16 measures a phase current lp which flows on the phase conductor 13 _; .

The phase voltage Vp and the phase current lp supply the electrical installation: 5.

The counter 1 further comprises a plurality of electrical components grouped into a functional metrology block; 20 and into an application functional block 21. The metrology functional block 20 and the application functional block 21 are separate and independent, so that a failure of one of the blocks does not cause a failure of the 'other block.

The metrology functional block 20 acquires the phase voltage measurements Vp and the phase current measurements lp, and transmits them to the application functional block 21.

The application functional block 21 includes processing means 22 and a memory 23.

The processing means · 22 comprise a processing component 24 (for example a processor, a microcontroller or an FPGA) adapted to execute · instructions: of a program for implementing the detection method. The processing component 24 fulfills other functions, and is in particular adapted: to manage the operation of the counter 1, to control the breaking device 12, to process the measurements carried out by the phase voltage sensor 15 and the phase current 16.

The memory 23: is a non-volatile memory capable of storing data to which; the processing component 24 has access /.

The detection method consists first of all / of measuring upstream of the breaking device 12 /, at regular intervals, the phase voltage Vp and the phase current

3/5 lp.

The measurements are performed by the phase voltage sensor 15 and the phase current sensor 16, then are acquired by the metrology functional block 20, and are processed by the application functional block.

21.

the phase voltage Vp and phase current Ip measurements are integrated over a duration of integration. The integration time is here equal to 1 minute, but could be different, and is not necessarily constant.

Integration allows stabilized phase voltage Vp and phase current Ip values to be obtained, without undergoing the effects of transient phases between two stages of phase current Ip consumed by the electrical installation 5.

The duration of a regular interval corresponds to the normal and usual sampling used to measure the electrical energy consumed by the electrical installation 5. Similarly, the integration of the measurements of phase voltage Vp and phase current Ip is also carried out as part of the measurement of electrical energy. The implementation of the detection method therefore does not require additional measurements compared to the measurements required by the usual operation of the counter 1.

The detection method then consists, when the phase voltage Vp (here, more precisely ·, the effective value of the phase voltage Vp) becomes lower than a predetermined voltage threshold, in opening the cut-off member.

The predetermined voltage threshold here is equal to

160 V.

Following. the opening of the breaking device · 12, if the phase voltage Vp returns to a normal voltage value, the processing component Zi detects a malfunction of the counter 1. The processing component 24 then generates an alarm message to destination of the Information System (SI) to prevent it from malfunctioning of the counter 1. The processing component 24 keeps the breaking device 12 open.

The alarm message is transmitted by carrier current online or by any other type of means of communication (wired or wireless'). In the case where on-line carrier currents are chosen, the DLMS and GOSEM application layers are advantageously used.

The alarm message is for example:

<EventNotificationRequesth <AttributeDesçriptor>

<Class ^: sId ¥ alùe = ''D'00l/>

<InstanceldValue = 00Q061620QFF />

<AttributeeldValue = 02 '' />

</AttributeDescriptor>

<AttributeValue>

0 CDoubleLongünsignedValue = 00000001 />

</AttributeValue>

</EventMotificatiohEequest>

The encoding associated with the corresponding alarm is:

G2 000 0010 00 0016200 FF020600000001,

It is noted that the communication by in-line carrier currents is managed by a communication component supplied by the electrical network 2 from a point located upstream from the breaking device · 12 ′, and that the in-line carrier currents are 'injected into the electrical network

2 from a point upstream of the cut-off device

12. Thus, the transmission of the alarm message by carrier current online is possible even when the breaking device 12 is open.

It is also noted that the detection of the malfunction of the counter 1 makes it possible to act in a preventive manner against the possible consequences of the malfunction. In

In this case, if the malfunction is a smashing of the breaking device 12, this malfunction could cause a fire · of the meter 1 or even of the electrical installation 5.

Following the opening of the breaking device 12, if the phase voltage Vp remains below the predetermined voltage threshold, the processing component 24 detects a collapse of the phase voltage Vp.

The processing component 24 then generates an alert message to prevent the phase voltage Vp from sagging, and closes the breaking device 12.

The normal voltage value, mentioned earlier, is defined according to the phase current Ip.

With reference to FIG. 2, the normal voltage value is included in a reference interval ïnt_ref around a reference voltage Vref, The reference voltage Vref depends on the current: of phase Ip.

A plurality of reference points Eref is thus defined, in a plane defined by an abscissa axis and an ordinate axis. Each brief reference point has a reference current value Iref on the abscissa and a reference voltage value Vref on the ordinate.

For each reference voltage Vref, the reference interval Int_rêf has for upper limit a maximum voltage VM equal to the value of the reference voltage Vref increased by 15%, and has for lower limit a minimum voltage Vm equal to the value from the reference voltage Vref reduced by 15%.

The curve GM thus represents the maximum voltage 'VM as a function of the phase current Ip, while the Curve Cm represents the minimum voltage Vm as a function of the phase current Ip.

Thus, for a phase current value Ip equal to a reference current Itef, the processing component 24 determines that the phase voltage Vp returns to a normal voltage value if the phase voltage Vp belongs to the interval of Int ^ ref reference defined by [Vref-15%; Vreff15%].

The reference points Pref are stored in a main table stored in the memory 23 of the application functional block 21. The main table is filled here with a granularity of IA for the phase current Ip.

Thus, following the opening of the cut-off member

12, to determine whether the phase voltage returns to a normal voltage value, the processing component 24 accesses the main table, identifies the reference current value Iref 'of the main table corresponding to the measured phase current - Ip, and uses the reference voltage Vref of the main table associated with said reference current value -Iref.

The process; detection also includes an automatic learning phase of the reference voltage

Vref as a function of phase current Ip. The sentence; machine learning aims to fill the main table with phase voltages Vp and phase currents- Ip actually measured; by the counter

1. The phase voltages Vp and the currents) of phase Ip which fill it: main table are measured when the breaking device 12 is closed, in the absence of a malfunction of the electric meter and of a subsidence of the phase voltage Vp.

The automatic learning phase consists first of all, for each new phase voltage Vp and new phase current Ip measured while the breaking device 12 is closed, to be integrated into a secondary table stored in the memory 23 a new point Pn defined by the new phase-phase voltage Vp and the new phase phase Ip.

Then, when the phase current Ip takes a value of a reference current Iref from a brief reference point (already stored in the main table), if the phase voltage Vp cbrrespôndàhtë is; included in

1 int erval the reference Int_ref around the reference voltage value Vref of said reference point In short, the processing component 24 integrates the new point 'En in the main table. The new point En, defined by the new phase voltage Vp and the new phase current Ip, becomes a brief reference point.

The automatic learning phase, which uses the secondary table and the concept of “new point ·”, is not immediately implemented from the installation of the counter 1. During a preliminary phase of predetermined duration, here equal to one week, all new En points are directly integrated into the main table.

It is noted here that, at the start of the method: of detection, following the opening of the cut-off member 12, when the processing component 24 attempts to determine whether the phase voltage Vp has taken over; normal voltage value and attempts :, to identify the reference current value in the main table; Iref corresponding to the phase current; Ip measured, several cases can arise :.

The simplest case is that the: main table does contain · a reference current value Iref equal: to the phase current Ip (at +/- IA maximum, due to the granularity: of IA of the main table).

However, it is possible that the main table does not yet contain a reference current value iref equal to the phase current Ip (a +/- IA).

If the nearest reference current value Iref differs from the phase current Ip, in absolute value, by a value less than or equal to a predetermined current deviation, a linear interpolation is used to estimate the reference voltage Vref used .

Bar against, if the reference current value:

In short, the closest differs from the phase current Ip, in absolute value, by a value greater than the predetermined current difference, the detection process closes the organ: cut-off 12 and keeps it closed.

The predetermined current difference is here equal to SA,

With reference to FIG. 3, the method for detecting a subsidence of a phase voltage of an electrified network according to a second embodiment of the invention is this time implemented by a three-phase electric meter 101.

The electrical network 102 is a three-phase electrical network comprising: three phases 103 and a neutral 104.

The counter 101 is intended to measure an electrical energy consumption supplied by the electrical network 102 to an installation: electrical · 105.

Counter 1 has three upstream phase terminals

106a, three downstream phase terminals 106b, an upstream neutral terminal 107 a and a downstream center terminal 107b.

The counter 101 also comprises three cut-off members 112 each mounted on the conductor of: phase 113 of one of the phases 103.

The counter 1 further comprises phase voltage sensors 115 for each of the phases (the three voltage sensors of: phase 115 are symbolized by only two resistors in FIG. 3, to improve the readability of F igure 3), and a phase current sensor 116 for each of the phases. The phase current sensors 116 are toroids.

The meter 101 again comprises a plurality of electrical components grouped into a metrology functional block 120 and into an application functional block

121.

The application functional block 121 includes processing means 122 and a memory 123.

The processing means 122 comprise a processing component 124.

The detection method according to the second embodiment consists in implementing the detection method according to the first embodiment described above for each of the phases 103, independently.

Qn therefore uses a main table by phase and a secondary table · by phase ;.

A phase slump is thus possibly detected for each phase 103, and automatic learning is carried out phase 103.

a phase for each

Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

All the numerical values provided here are used to illustrate the invention, and may of course be different when practicing the invention.

The electrical architecture of the single-phase meter and that of the three-phase meter can also be different :. The components used can of course be · different ·. In particular, it is possible to use different voltage sensors and current sensors.

The invention applies of course to any polyphase meter (and to any polyphase electrical network).

Claims (11)

RESELL! CATIONS 1. Method for detecting a subsidence of a phase voltage (Vp) present on a phase (3; 103) 5 of an electrical network (2; 102), the detection method being implemented by an electrical meter) (1; 101) which is connected to the electrical network and which comprises- a cut-off member 112; 112) mounted on a phase conductor (13; 113) · connected to phase (3; 103), the process 10 detection comprising the steps: - to measure, upstream of the breaking device and at regular intervals, the phase voltage (Vp) and a phase current (Ip) flowing on the phase conductor (13); 15 - when the phase voltage falls below a predetermined voltage threshold, to open the < break; - following the opening of the breaking device, if the phase voltage resumes - a normal voltage value Defined) as a function of the phase current (Ip), to detect a malfunction of the electric meter, to generate an alarm message to prevent the malfunction of the electric meter, and to keep the cut-off device open; 25 - following the opening of the cut-off device, if the phase voltage remains · below the predetermined voltage threshold, to detect a drop in the phase voltage (Vp), to generate an alert message to prevent sagging of the phase voltage, and 30 close the organ: cut-off (12; 112). 2. Detection method - according to claim 1, in which the normal voltage value · is included in a reference interval () Int__ref) around a reference voltage (Vref) which depends on the current of 35 phase (Ip). 3. Detection method according to claim 2, in which the reference voltage (Vref) comes from a main table stored in a memory (23; 123) of the electric meter, said main table comprising a plurality of reference points (Pref) each defined by a value of reference voltage (Vref) and a reference current value (Iref). 4. Detection method according to claim 3, further comprising an automatic learning phase ⁷ of the reference voltage (Vref) as a function of the phase current (Ip). 5. Detection method according to claim 4, in which the automatic learning phase comprises the steps: r - in the absence of a malfunction of the electric meter and of a subsidence of the phase voltage (Vp), to measure a new phase voltage and a new phase current while: that n organ: of cutoff is closed; - integrate into a: secondary table a new point (Pn) defined by the new phase voltage and the new phase current; - then, when the phase current (ïpj takes a reference current value (Iref :) from a reference point (Pref), if the associated phase voltage (Vp) is included - in the reference interval around of the reference voltage value of said reference point (Pref), to integrate the new point in the main table, the new point (Pn) then becoming a reference point (Pref). 6. Process; detection according to claim 5, in which, during a preliminary phase of predetermined duration, all the new points (Pn) are introduced directly into the main table. 7. Method for detecting a subsidence of at least one phase voltage of a polyphase electrical network, consisting in implementing, for each phase, independently, the detection method according to one of the preceding claims. 8. Detection method according to claim 1, in which the detected malfunction of the electric meter is a smashing of the breaking member. 9. Electric meter comprising a cut-off device (12; 112), a voltage sensor (15; 115), a current sensor (16; 116), and a processing component (24; 124) arranged to activate implements the detection method according to one of the preceding claims. 10. Computer program instructions for implementing, electric, the detection method according to one of the preceding claims. 11. Storage means, characterized in that they store a computer program comprising instructions for implementing, by an electric meter, the detection method according to one of claims 1 to 8. comprising of by a counter